1. Field of the Invention
The present invention relates to a method of fixing a flavorant which improves the smell of sidestream smoke of tobacco, as well as a cigarette, and more specifically, to a method of effectively fixing a flavorant on a tobacco wrapper paper without substantially modifying a flavorant to be fixed, as well as a cigarette.
2. Description of the Related Art
A number of flavorants are added to tobacco articles, such as cigarettes, to create various types of tastes and aromas of tobacco smokes. In general, many kinds of volatile flavorant are blended and added to tobacco articles to create a distinctive impression of an individual tobacco product. In recent years, to improve the smell of the sidestream smoke released to the ambient during smoking, it has been proposed to add, to cigarette paper, a flavorant that masks the unpleasant smell.
The flavorants, which are added to cigarette paper to improve the smell of the sidestream smoke, are required to have properties, including those properties that the flavor is not released undesirably to the site where the tobacco article is produced, that the flavorant is not transferred to other materials while the tobacco article is in storage, and yet that the flavorant is selectively released in the sidestream smoke during smoking in order to improve the smell of the sidestream smoke. In order to establish such a smell-improving technique, there must be provided a flavor-releasing agent which can suppress the volatilization of the flavorant to a low level, and is stable and non-volatile under production and storage conditions, and yet which releases the flavor by thermal decomposition or desorption during smoking.
As such a technique, Jpn. Pat. Domestic Announcement No. 2-501075 (U.S. Pat. No. 4,804,002) discloses a technique of convering a flavorant into its glycoside, and Jpn. Pat. Appln. KOKAI Publication No. 5-146285 (U.S. Pat. No. 5,144,964) and Jpn. Pat. Domestic Announcement No. 7-504080 (U.S. Pat. No. 5,479,949) disclose a technique of clathrating a flavorant by cyclodextrin.
Incidentally, it is strongly desired that the masking flavorants used to improve the smell of the sidestream smoke should be used while being blended with various kinds of volatile masking flavorants so as to assure the unique aroma of the smoke that each type of the tobacco products has, as in the case of the general flavorant discussed above. However, the masking flavorants solved by the above-described technique are restricted by the synthesizing method in the technique of converting into glycoside and by the physical conditions of the enclosing cavity in the clathrate technique with cyclodextrin. Further, these techniques cannot deal with blended flavorants.
On the other hand, the taste and smell of a cigarette are created by smoking it, and the generation mechanism of the taste and flavor is an aggregate of considerably complicated processes. For example, generation of smoke component by, e.g., chemical reactions such as combustion reaction and oxidization reaction, evaporation and a distillation process and delivery of a smoke component by a transfer process such as dilution, diffusion or filtration are interacted with each other. Therefore, if a novel compound or additive which has not been conventionally available is used as a flavorant-holding member (fixing medium), an unexpected byproduct may be created due to the above complicated processes, which may bring about a negative affect on the taste and aroma of the cigarette. As a result, a great deal of efforts may be required to remove the negative effect in order to produce satisfactory taste and flavor.
In summary, as a generally employable flavor-holding and fixing technique used in the production of tobacco articles, a technique which does not affect the generation and delivery of smoke components, that is, a flavor-fixing technique which does not use a novel compound or additive is desirable.
Therefore, firstly, it is an object of the present invention to provide a method of fixing flavorants which improve the smell of sidestream smoke of tobacco, such that the flavorants can be stably held on tobacco wrapper paper during storage and can release the flavor which improves the smell of the sidestream smoke during smoking.
A second object of the present invention is to provide a method of effectively fixing, to tobacco wrapper paper, existing flavorants for improving the smell of sidestream smoke without a special modification made to the flavorant.
The inventors of the present invention carried out extensive studies in order to achieve the above objects, and have found that an emulsion of an ethylene-vinyl acetate copolymer (hereinafter referred to as xe2x80x9cEVAxe2x80x9d), if it has a specified range of ethylene contents, is very effective as a medium for fixing a flavorant(s) for improving the smell of sidestream smoke of the tobacco (hereinafter referred to also as xe2x80x9cmasking flavorantxe2x80x9d), and there is no need then to effect special modifications (e.g., reactions with other compound, clathrations) to the flavorant. At the same time, they have also found that the solid content of the EVA emulsion influences the stable retention of the masking flavorant. Further, the inventors of the present invention have found that when a masking flavorant is added to an EVA emulsion, it is effective that the masking flavorant is added as an ethanol or propylene glycol solution, and, in that case, the amount of the ethanol or propylene glycol added as a solvent influences the stable retention of the masking flavorant. Then, they have accomplished the present invention by studying these factors.
Thus, according to the present invention, there is provided a method of fixing a flavorant for improving the smell of a sidestream smoke of tobacco, comprising the steps of: applying, to tobacco wrapper paper, a tobacco sidestream smoke smell-improving agent comprising an ethanol or propylene glycol solution of a flavorant for improving the smell of the sidestream smoke of tobacco added to an emulsion of an ethylene-vinyl acetate copolymer having an ethylene content of 30% by weight or less, the emulsion having a solid content of 10 to 60% by weight; and drying the improving agent to fix the flavorant to the wrapper paper with the ethylene-vinyl acetate, wherein the ethanol solution of the flavorant is added to the emulsion such that an amount of ethanol is 40 parts by weight or less with respect to 100 parts by weight of the emulsion, or the propylene glycol of the flavorant is added to the emulsion such that an amount of propylene glycol is 11 parts by weight or less with respect to 100 parts by weight of the emulsion.
Further, according to the present invention, there is provided a cigarette having a tobacco rod wrapped by tobacco wrapper paper to which a masking flavorant is fixed by the method of the present invention. In this case, it is most preferable that the EVA emulsion should be applied in the form of a seam adhesive at a seamed portion of the tobacco wrapper paper.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.